The job
Modelled, not recorded. Every figure on this page is re-run through the calculator it names whenever the site is built; the estimate is worked, but no job was carried out, so the last section gives the mechanism of each likely error rather than a measured overrun.
A privacy fence looks like one long quantity and orders as six: posts, concrete, rails, pickets, fasteners and stain. Half of them follow from where the posts stand rather than from the length, and the posts follow from two decisions taken before anything is counted — how the fence meets the slope, and where the gate goes. The calculators below run in that sequence: the grade decides the length the posts are counted on, the posts decide the holes, and the holes decide the concrete.
The job: one straight 150 ft (45.7 m) boundary run of 6 ft (1.83 m) pressure-treated pine privacy fence — 4x4 posts at 8 ft (2.44 m) centres, three 2x4 rails to a bay, 1x6 dog-ear pickets butted edge to edge — with a walk gate hung in a 4 ft (1.22 m) bay at the uphill end. The ground falls 3 ft (0.91 m) evenly from the gate to the far end. The model assumes the local frost line is no deeper than the 24 in (610 mm) the line posts go down; where it is deeper, the holes deepen and every concrete figure after them moves with them. Each hole is filled with concrete for its whole depth, which is what the post-hole calculator assumes, so the gravel base the setting guide puts under a post foot for drainage is outside every figure here.
THE GATE CHANGES THE LENGTH EVERYTHING IS COUNTED ON. Take the gate bay out and 146 ft (44.5 m) of fence remains, and that — not the 150 ft (45.7 m) on the survey — is what the posts, rails and pickets are counted against. The gate then adds the one post the fence count cannot see, and both of its posts want wider, deeper holes than the line posts, as does the post that closes the far end of the run. No calculator on this site counts a gate leaf, its hardware or the picket nails, so each is named at the step where it comes up, with no number attached.
THE SLOPE IS SETTLED FIRST BECAUSE IT SETTLES THE POSTS. At this grade the fence can rack — rails running parallel to the ground, pickets hanging plumb — so every post stands the same height above its own patch of ground and the line posts stay inside an 8 ft (2.44 m) stock length. Stepped instead, each bay would sit level and most posts would have to stand a step taller than the fence, with an open gap below every bay that deepens toward its downhill post.
WHAT THIS PAGE IS, AND WHICH SUMS ARE DONE BY HAND. No fence stands behind these numbers: the job is a model, and each calculator runs on the inputs printed beside it. Three figures are added up by hand from what the calculators return, and are labelled where they appear — the 21st post, which is the fence count plus the gate's latch post; the 39-bag concrete total, which adds the two hole sizes together; and each post's length, the fence height plus its hole's embedment: 6 ft plus 24 in and 6 ft plus 36 in (1.83 m plus 610 mm and 914 mm). The closing section is about the ways a fence order tends to miss — holes dug bigger than drawn, boards refused off the truck, thirsty wood, a gate bought last — and which side of the figure each one pushes, not about any measured result.
What was measured, and how
Length of the fence line, end post to end post
150 ft (45.7 m), one straight run with no corners
Pulled along a taut string between the two end stakes and checked against the lot survey, not walked along the ground or along an old fence. A tape that sags or detours round shrubs adds length that is not there, and pegging off an existing fence inherits every error it was built with.
The gate bay, post centre to post centre
4 ft (1.22 m) at the uphill end, leaving 146 ft (44.5 m) of fence
Set from the leaf width plus its hinge and latch clearances, then recorded centre to centre so it subtracts cleanly from a run that was also measured to centres. Subtracting the gap measured between the two posts' inside faces instead leaves the fence length a full post width out.
Fall along the line
3 ft (0.91 m) over the 150 ft (45.7 m), spread evenly, no break of grade and no cross-fall at the gate
Read from a line level on the taut string, or from a laser, at each post position and logged as its height under the gate end. Readings at the two ends alone cannot tell an even fall from a hump in the middle, and the two need different fences.
Hole depth, checked against frost
24 in (610 mm) for the 18 line posts; 36 in (914 mm) for the far end post and the two gate posts; concrete for the full depth of each
Started from a third of the height above ground and then checked against the frost depth the local building department publishes; where frost goes deeper, frost governs. Taking the depth from the rule of thumb without the frost check is how a fence stands through summer and heaves out of line in its first winter.
Post and picket sizes as delivered
4x4 posts; 1x6 dog-ear pickets — standard dressed sizes from step 3, confirmed with a tape on delivery
Taken as the standard dressed size for each nominal, then checked with a tape on the delivered stock rather than trusted from the label. A nominal 4x4 or 1x6 is smaller once dressed, and feeding the label size into the arithmetic overstates the volume each post takes out of its hole and undercounts the pickets across a long run.
Buried utilities along the line
Utility locate before any digging; private lines swept at each stake
An 811 locate request marks the utilities' own lines up to each meter, but not private runs such as irrigation, landscape lighting or a feed to a detached garage, so those are swept for with a detector along every hole position. Treating the utility paint as the whole picture is how an auger finds a sprinkler main.
The takeoff, in order
Each step needs something from the one before it, which is why the order is part of the answer.
Read the grade, and decide whether the fence rakes or steps
- Needs
- The 3 ft (0.91 m) fall and the 150 ft (45.7 m) horizontal length from the measurements — taken as one grade for the whole run only because the model assumes no break of grade along it.
- Produces
- A 2.0% grade, or 1.15°. That is gentle enough to rack, and too small for a length taken over the grass and one taken along a level string to differ by anything a count would notice, so the plan length stands for every later step. Stepped at the nominal 8 ft (2.44 m) spacing, each bay would drop just under 2 in (about 49 mm) below the one before and push most posts past an 8 ft (2.44 m) stock length — the reason this comes before anything is counted.
Result2.0% grade (1.15°), from 3 ft of fall in 150 ft (0.91 m in 45.7 m)
Slope & Grade CalculatorCount the posts, bays and rails on the fenced length
- Needs
- The 146 ft (44.5 m) left once the gate bay is taken out, the 8 ft (2.44 m) spacing and the 5–7 ft (1.5–2.1 m) height band — and the racking decision from the grade, which lets the plan length stand in for the length along the ground.
- Produces
- 20 posts for 19 bays, and 57 rails at three to a bay. Spread evenly the bays set out at 7.68 ft (2.34 m) rather than leaving one short bay at the end, so every rail comes from one 8 ft (2.44 m) 2x4, trimmed. The gate's latch post is the one post this count cannot see, which makes 21 by hand. Of this run's two end posts, the one at the gate becomes the hinge post and the other closes the far end; both join the latch post in the deeper holes, leaving 18 line posts.
Result20 posts, 19 bays and 57 rails (bays of 7.68 ft / 2.34 m)
Fence CalculatorTurn the nominal sizes into the ones the arithmetic uses
- Needs
- The members the post count counted but did not size — the 4x4 posts and 2x4 rails the job specifies — plus the 1x6 pickets, because the next three steps work on the wood's dressed size, not its name.
- Produces
- A 4x4 is 3.5 × 3.5 in (89 × 89 mm) once dressed, which is the post width the concrete steps deduct from each hole. The same table gives a 1x6 as 5.5 in (140 mm) across the face, which is the picket width the picket count divides by. The lookup stops at 4x4, so a heavier 6x6 hinge post cannot be checked here.
Result3.5 × 3.5 in actual (89 × 89 mm)
Lumber Dimensional Size CalculatorSize the concrete for the eighteen line-post holes
- Needs
- The 18 line posts from the post count (its 20, less the two end posts that go into the deeper holes), the 3.5 in (89 mm) dressed width from the size lookup, and the 24 in (610 mm) depth set by the fence height and checked against frost, in a 10 in (254 mm) auger hole.
- Produces
- 0.61 yd³ (0.47 m³) with each post's own volume already deducted, which the calculator turns into 28 bags of 80 lb (36 kg) mix. The 10 in (254 mm) auger is the common size nearest the three-times-the-post-width rule. The figure fills each hole with concrete to the bottom; drainage gravel bedded beneath a post would be dug below that depth and is not in it.
Result0.61 yd³ (0.47 m³), 28 bags of 80 lb (36 kg)
Post Hole Concrete CalculatorSize the end and gate-post holes on their own, wider and deeper
- Needs
- The far end post and the two gate posts set aside at the post count, and the same 3.5 in (89 mm) post width, but a 12 in (305 mm) hole taken to 36 in (914 mm): the calculator's own help puts end and gate posts in larger, deeper holes, and the hinge post carries the leaf as a cantilever on top of its share of the wind.
- Produces
- 0.23 yd³ (0.18 m³), which the calculator rounds up to 11 bags of 80 lb (36 kg) — the geometry comes to just over ten and a half, so the last bag is about half spare. Added by hand to the line posts, that is 39 bags. A 6 ft (1.83 m) fence on 36 in (914 mm) of embedment needs a 9 ft (2.74 m) post, so these three come from 10 ft (3.05 m) stock; hung from its downhill post, the leaf gains clearance as it swings open instead of scraping.
Result0.23 yd³ (0.18 m³), 11 bags of 80 lb (36 kg)
Post Hole Concrete CalculatorCount the pickets on the fenced length
- Needs
- The 146 ft (44.5 m) of fence from the post count with the gate bay excluded, the 5.5 in (140 mm) face width from the size lookup, no gap, and the racked layout from the first step, which keeps the picket line unbroken past every post.
- Produces
- 335 pickets, from 318.5 before the reject allowance. They are butted because treated pine arrives wet and shrinks, opening its own narrow gaps as it dries. The gate leaf's pickets are not in this figure — a leaf is built on its own frame — and nothing on the site counts the nails that fix all of them to the rails.
Result335 pickets (5.5 in / 140 mm face, butted)
Fence Picket CalculatorQuantify the stain, one coat at a time
- Needs
- The full 150 ft (45.7 m) line from the measurements — the gate leaf takes stain like any bay — the 6 ft (1.83 m) height, and both faces, applied once the pickets from the step above have dried enough to absorb it.
- Produces
- 12 gallons (45 L) for one coat over 1,800 sq ft (167 m²) of face, at the calculator's rate for rough-sawn wood. One coat is often the whole job for a semi-transparent stain, while a solid stain usually wants a second, so the order is this figure times the coats intended, bought as one batch. Sprayed on, it still wants brushing into the rough-sawn face straight after, so it soaks in rather than sitting on the fibres.
Result12 gallons per coat (45 L), over 1,800 sq ft (167 m²) of face
Wood Fence Stain Calculator
The figures
| Step | Calculator | Figure |
|---|---|---|
| Read the grade, and decide whether the fence rakes or steps | Slope & Grade Calculator | 2.0% grade (1.15°), from 3 ft of fall in 150 ft (0.91 m in 45.7 m) |
| Count the posts, bays and rails on the fenced length | Fence Calculator | 20 posts, 19 bays and 57 rails (bays of 7.68 ft / 2.34 m) |
| Turn the nominal sizes into the ones the arithmetic uses | Lumber Dimensional Size Calculator | 3.5 × 3.5 in actual (89 × 89 mm) |
| Size the concrete for the eighteen line-post holes | Post Hole Concrete Calculator | 0.61 yd³ (0.47 m³), 28 bags of 80 lb (36 kg) |
| Size the end and gate-post holes on their own, wider and deeper | Post Hole Concrete Calculator | 0.23 yd³ (0.18 m³), 11 bags of 80 lb (36 kg) |
| Count the pickets on the fenced length | Fence Picket Calculator | 335 pickets (5.5 in / 140 mm face, butted) |
| Quantify the stain, one coat at a time | Wood Fence Stain Calculator | 12 gallons per coat (45 L), over 1,800 sq ft (167 m²) of face |
The waste factors, and why these ends of the ranges
| Material | Applied | Why |
|---|---|---|
| Pickets | The calculator's default reject allowance, not its higher setting | The run is straight with no corners, and on a racked fence the pickets pass across the post faces in one continuous line, so the only ripped pieces are the closers at the two ends. What the 5% really covers is the delivery — split ends, loose knots and boards too twisted to nail flat. The calculator's own help reserves the 10% setting for runs with corners and many short bays, and this one has neither. |
| Post-hole concrete | Whole bags as the calculator rounds them, with over-dig checked on site rather than allowed for | Both bag counts are rounded up from the hole geometry, and the end-and-gate count already carries about half a spare bag. The variable that matters is the hole itself — an auger that wanders or a hole that bells out at the top takes more concrete than any flat percentage predicts, so it is measured after the first few holes instead of guessed at. |
| Rails | One 8 ft (2.44 m) 2x4 for every rail, trimmed to the bay, with rejects picked out at the yard | The bays set out at 7.68 ft (2.34 m), so each rail is one stock length with a short offcut, and joining rails mid-bay to save lumber weakens the member that carries the pickets' wind load into the posts. The real loss is crowned or twisted boards, which are cheaper to refuse at the yard than to fight on the fence. |
| Posts | Whole stock lengths chosen for the embedment, not a percentage | A 6 ft (1.83 m) fence on 24 in (610 mm) of embedment uses all of an 8 ft (2.44 m) 4x4, which leaves nothing for an over-deep hole or a split end cut off. The far end post and the two gate posts need 9 ft (2.74 m) and so come from 10 ft (3.05 m) stock, which makes 18 of the shorter length and 3 of the longer. Had the slope forced a stepped fence, most line posts would have moved onto the longer stock too. |
| Stain | Every coat bought together, in one batch | The calculator's figure is one coat at 150 sq ft (about 14 m²) to the gallon on rough-sawn wood, so a second coat doubles it. Buying all of it at once matters more than any allowance: cans mixed in a later batch can come out a shade off, and along 150 ft (45.7 m) of straight fence the join between the two is visible from either end. |
Where this estimate is most likely to be wrong
Concrete for the post holes
usually underThe calculator assumes a clean cylinder exactly the auger's diameter. Real holes flare at the top where the spoil is worked loose, belly out in sandy ground and are often taken past the planned depth, and each of those adds concrete. Across twenty-one holes the extra comes to bags, not shovelfuls.
Narrow it by: Digging the first two or three holes, measuring their real width and depth, and re-running both concrete steps on those figures before ordering.
Pickets
either wayDividing the run by the face width is exact, so the uncertainty sits in the bundles themselves. A well-graded load leaves spares, while bundles of split or twisted boards eat through the allowance quickly. A change of mind from racked to stepped partway along also adds a ripped closer at every post.
Narrow it by: Opening the bundles on delivery and sorting out the rejects before any are nailed up, while the store can still swap them.
Stain
usually underThe calculator covers a flat rectangle on each face. The back of the fence also carries three rails and the post faces, all of which take stain, rough-sawn pickets soak up more than smooth boards, and the first coat into unsealed wood sinks in deeper than any later one, so it spreads over less face per gallon than the rate allows.
Narrow it by: Staining one full bay first, noting what it takes, and scaling that by the number of bays before buying the rest.
Hole depth where the ground freezes
usually underEvery depth on this page assumes the frost line sits above the bottom of a 24 in (610 mm) hole. In a colder county the building department's frost depth governs, every hole goes deeper, and the concrete, the post lengths and the digging time all rise with it; no amount of extra concrete in a shallow hole stops heave.
Narrow it by: Asking the building department for its frost depth before the auger is rented, and re-running both concrete steps at that depth.
The gate leaf and its hardware
usually underNothing on this page counts the leaf: its frame, its pickets, the diagonal brace, the hinges, the latch and a gate stop. It is the line most often missing from a fence order because the fence arithmetic stops at the gate posts, and the hardware tends to be bought last from whatever is on the shelf.
Narrow it by: Drawing the leaf out at full size with its frame and brace, and listing its lumber and hardware as a separate order.
The waits inside the schedule
usually underThe materials arrive at once and the framing goes quickly, but two waits sit inside the job: the post concrete has to gain strength before rails and pickets load it, and treated pickets delivered wet have to dry before they take stain evenly — weeks rather than days. A fence built and stained in one weekend is usually stained too soon.
Narrow it by: Planning the stain as a separate visit, and sprinkling water on a picket first: it is ready when the water soaks in rather than beading.
Tools this job needs
Frequently asked questions
- How many pickets does a 150 ft, 6 ft privacy fence need?
- On this modelled job, 335. The 4 ft (1.22 m) gate bay comes out first, leaving 146 ft (44.5 m) of fence; with 5.5 in (140 mm) pickets butted edge to edge that is 318.5 pickets, and the calculator's default reject allowance takes it to 335. The gate leaf needs its own pickets on top. Leaving a gap between pickets lowers the count, and a narrower picket raises it.
- How many posts and bags of concrete does 150 ft of fence take?
- Twenty-one 4x4 posts here: 20 for the 19 bays at 7.68 ft (2.34 m) centres, and one more for the gate. The 18 line posts, in 10 in (254 mm) holes 24 in (610 mm) deep, take 28 bags of 80 lb (36 kg) mix; the far end post and the two gate posts, in 12 in (305 mm) holes 36 in (914 mm) deep, take 11. That is 39 bags before any hole is dug wider than planned.
- How much stain does a 150 ft privacy fence take?
- About 12 US gallons (45 L) for each coat on both faces. The calculator treats the 150 ft by 6 ft (45.7 by 1.83 m) fence as 1,800 sq ft (167 m²) of face and allows 150 sq ft (about 14 m²) to the gallon on rough-sawn wood, so a two-coat solid stain doubles it. The rails, the post faces and a thirsty first coat push the real figure up rather than down.